A sequence of branches from the aorta supply circultation to the pelvis, buttocks and legs. These are named as follows
FEMORAL (groin level)
POPLITEAL (knee level)
A bypass procedure is the commonest open surgical procedure carried out in the lower limb for ischaemia. The precise name given to the procedure depends on where the bypass starts and finishes, (ie, aorto-femoral, ilio-femoral, femoro-popliteal, femoro-tibial and popliteal-pedal bypass). Artificial Dacron or PTFE grafts are used to bypass larger arteries, but below the groin the smaller femoral and popliteal vessels are often best bypassed using the patients own vein. The long saphenous vein is ideally situated for this.
These procedures require a general or regional anaesthetic and therefore the fitness of the patient is a key factor in deciding whether or not to expose them to the risks of surgery.
Pre-operative preparation is also vitally important in order to optimize the patients cardiac, respiratory, and renal function.
The principle underlying these bypass operations is to expose and control the inflow and outflow artery above and below the diseased segment. The arteries can then be clamped and opened and the graft sewn on at both ends. At release of clamps blood will then flow through the graft, bypassing the diseased segment.
Major complications occur in apporximately 5-8% of cases. The commonest local complications after surgery are thombosis leading to occlusion of the graft, bleeding, and infection. The latter is more common with artificial grafts. Patients with vascular disease frequently have co-morbid conditions and are therefore prone to a number of general post operative problems (ie, heart attack, chest infection, DVT/PE, kidney function). Good post operative care helps to minimise these complications.
Surgery is usually reserved for severe limb ischaemia, where there is concern that leaving the poor circulation will damage the leg and risk amputation. The risks of surgery are then worthwhile.
For more information visit the section at the Circulation Foundation